Barrels or similar containers filled with highly viscous materials, for example a silicone paste, are usually emptied by pushing a piston into the open barrel. The highly viscous material can be pushed and conveyed out of the barrel through pipelines. It is also possible to push, as a part of the piston or in place of the piston, the lid of the barrel into the inside of the barrel in order to empty same.
Depending on the viscosity of the material to be emptied from the barrel, a considerable amount of pressure is needed in order to push the material into the pipeline. This causes the barrel to be exposed to very high mechanical stress during the emptying operation.
For reasons of weight and expense, barrels are usually designed with very thin walls and have a stability which is just sufficient to avoid damage to the barrel during transport. However, the barrel is not designed to withstand the stress occurring during an emptying thereof. For example, such barrels are made of plastic or cardboard.
To prevent the barrel from bursting due to the high pressure developed during emptying of the barrel, the state of the art suggests to place split metal sleeves or half-shells, for example of sheet metal, around the barrel and to enclose and reinforce same in this manner. The mounting and closing off of the half-shells or sleeves is very complicated, requires a considerable amount of manual labor and is, therefore, disadvantageous.
It furthermore has proven to be disadvantageous that the sleeves or half-shells must be adapted in an exact manner to the outside dimensions of the barrel, so that with a device on which many different barrel sizes are to be emptied, a number of such sheet-metal sleeves or half-shells are needed.